Graft diameter does not influence primary stability of ulnar collateral ligament reconstruction of the elbow

Abstract

BackgroundUlnar collateral ligament insufficiency may result in medial elbow pain, instability, and reduced athleticperformance in throwing athletes. Several reconstruction methods have been described, but biomechanical studies suggest that in general, stability of the graft construct is inferior to the native ulnar collateral ligament. This study investigates whether a stronger graft would yield greater resistance to valgus load over the range of motion MethodsTen cadaveric elbows were mounted to a testing fixture and incremental valgus moments of 2.5, 5, and 7.5Nm were applied with the elbow in 120°, 90°, 60°, 30° and 0° of flexion and in varying rotational forearm positions. The intact and the ulnar collateral ligament released elbow joint were compared with the docking ulnar collateral ligament reconstruction technique, using different graft sources with increasing cross-sectional areas: palmaris longus, tricpes brachii, extensor carpi radialis longus, and semitendinosus. The resulting angular displacement wasevaluated and compared between graft sources and different elbow positions. ResultsCompared with the intact situation, ulnar collateral ligament release resulted in a significant increase invalgus deformation over the entire range of flexion–extension motion. Ligament reconstruction using any graft source significantly restored valgus stability at 60°, 90°,and 120°, while at 0° and 30°, angular valgus deformation did not significantly differ from the ulnar collateral ligament deficient situation. There were no significant differences in angular valgus deformation between the graft sources over the range of flexion motion or forearm rotation ConclusionsThis study did not prove that a thicker graft yielded more resistance to valgus moments when usingthe docking technique. Thicker grafts require larger bone tunnels, cannot be adequately tensioned, and are non-anatomic.Therefore, the palmaris longus or a triceps tendonstrip are considered more appropriate for ulnar collateral ligament reconstruction.